The field of the invention is fence posts and the invention relates more particularly to concrete fence posts.
A large amount of lumber each year is used to make fence posts. Such posts are supported in the ground either by the wood contacting the ground or preferably by pouring concrete around a post which is placed in a post hole. Unfortunately, such posts are subject to attack by termites and also subject to rot and even treated posts have a life of only about 10 to 15 years in anything but the most arid of climates. The posts then have to be replaced which also consumes a substantial amount of additional wood and which is once again subject to destruction by termites, rot and other forces.
Concrete has been used since the Roman Empire. Concrete pillars are used in construction of buildings, bridges and the like. Concrete fence posts are known but are typically prefabricated such as that shown in U.S. Pat. No. 4,193,584. Such fence posts, although free from destruction by termites and rotting, are expensive and very heavy. This weight makes them very difficult to use without specialized lifting apparatus. Another patent showing a prefabricated cement post is U.S. Pat. No. 3,614,068. A reinforced fence pole made from concrete is shown in U.S. Pat. No. 4,637,186 where the pole is fabricated in a mold, cured and then removed and inserted into the ground. A cast-in-place prestressed concrete piling is shown in U.S. Pat. No. 4,915,544 which has a moveable casing and forms a concrete pile in the ground. The Wells U.S. Pat. No. 4,767,241 discloses a method for forming footings and piers in concrete construction. This patent shows a one-time used plastic footing mold upon which a cardboard tube of the type sold under the trademark "SONOTUBE" is placed and this permits the footing to be formed at the same time the pier is formed.
None of these processes suggest a reusable form for concrete fence posts.